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Monitor · backlight bleed test

Backlight Bleed Test: Bleed, IPS Glow or Normal?

This backlight bleed test shows a full-screen black image so you can see light leaking around the edges of an LCD. Three questions then tell you whether it's normal IPS glow (shifts as you move your head — a panel characteristic, not a defect), mild bleed (fixed patches you only see at high brightness in a dark room — common), or bleed you can see in normal use (worth a return). OLED screens have no backlight, so they can't bleed. Nothing is uploaded.

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How the backlight bleed test works

  1. Step 1

    Dark room, normal seat

    Dim the lights and sit where you normally sit. Use your usual brightness first, then try maximum.

  2. Step 2

    Full-screen black

    Look at the edges and corners. Then move your head left, right, up and down and watch whether the light patches move or change colour.

  3. Step 3

    Answer three questions

    Did you see glow, does it change with angle, and can you see it in normal use? The answers separate IPS glow from real bleed.

Backlight bleed vs IPS glow: how we decide

ResultWhat it meansWhat to do
No visible bleedThe black screen looks even.Nothing to do.
IPS glow (normal for IPS)Glow that shifts or changes colour as you move your head is IPS glow — a property of IPS panels, not a defect.Usually not covered by warranty. Lower brightness, add some room light, or sit further back. If it bothers you, return it within the retailer's window.
Mild backlight bleedFixed patches that only show at high brightness in a dark room — common on LCDs.Usually within tolerance. Keep using it; if it's within the return window and bothers you, exchanging is reasonable.
Noticeable backlight bleedFixed bright patches you can see in normal use — light leaking past the panel edge.If you're within the retailer's return window, return or exchange now. Otherwise contact the brand's support with a photo of the black screen.
Glow on an OLED — worth checkingOLED has no backlight, so true backlight bleed can't happen. Glow on black usually means a raised-black setting or a near-black uniformity issue.Check picture settings (black level, HDR, brightness boost), then retest. If patches remain, contact support.

What this test can and can't tell you

  • Reliable: Shows what's there. A full-screen black image in a dark room is the standard way to reveal backlight bleed and IPS glow.

  • Estimate: Severity is your judgement. Cameras exaggerate bleed badly, and eyes adapt to the dark. Judge at the brightness and room lighting you actually use.

  • Limit: Not a uniformity measurement. It can't measure luminance uniformity in nits like a colorimeter — it tells you whether what you see is typical or a defect.

Backlight Bleed Test — frequently asked questions

How do I test for backlight bleed?
Show a full-screen black image in a dim room at your normal brightness, then at maximum. Light patches that stay fixed at the edges or corners are backlight bleed. Glow that moves or changes colour as you shift your head is IPS glow. This page walks you through it and gives a verdict.
What's the difference between backlight bleed and IPS glow?
Backlight bleed is light leaking past the edge of the LCD panel, usually from uneven pressure in the frame; it stays in the same place whatever your viewing angle. IPS glow is a property of IPS panels viewed off-axis: it changes intensity and colour as you move your head and is strongest in the corners at an angle.
Is some backlight bleed normal?
Yes. Almost every LCD leaks a little light at the edges in a dark room at high brightness. It's a problem when you can see it in normal use — with room light at your usual brightness — or when it shows up as bright blotches in dark scenes.
Can backlight bleed be fixed?
Sometimes slightly: bleed caused by frame pressure can ease over the first weeks, and some people loosen the screws on the back of the monitor (this can void the warranty). The dependable fix is an exchange within the return window. Lower brightness and some room light make it less visible.
Do OLED monitors have backlight bleed?
No. OLED pixels make their own light, so there's no backlight to leak. Glow on black on an OLED usually comes from a setting that raises black levels, or from near-black uniformity issues.

Sources

  1. How to distinguish IPS glow and light leakage in a Dell monitor — Dell
  2. LCD screen light leakage judgement — ASUS
  3. What is IPS glow and how can I make it less visible? — BenQ
  4. What is backlight bleed or backlight leakage? — BenQ

Last reviewed .

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